[Hawkular-dev] [Metrics] Pluggable aggregation functions: next steps

[Thomas Segismont]

Thanks for the pointers, we'll have a look.

Le 21/07/2015 23:27, Jay Shaughnessy a écrit :
>
> Right, you may find what you need is already in place, or you may find
> that you can spend time on higher-level functions.  In particular, see:
>
> MetricsService:
> <T> Observable<T> findGaugeData(String tenantId, MetricId id, Long
> start, Long end,Func1<Observable<DataPoint<Double>>, Observable<T>>...
> funcs);
>
> Aggregate:
> predefined functions.
>
> Here is an example snippen from
> org.hawkular.alerts.external.metrics.Manager to gather multiple
> aggregates in one call and determine the range:
>
>                      case range: {
>                          Iterator<Double> iterator =
> metrics.findGaugeData(tenantId, metricId, start, end,
>                                  Aggregate.Min, Aggregate.Max)
> .toBlocking().toIterable().iterator();
>                          Double min = iterator.next();
>                          Double max = iterator.next();
>                          value = max - min;
>                          break;
>                      }
>
>
> -Jay
>
> On 7/21/2015 10:43 AM, John Sanda wrote:
>> Keep the following in mind. Since the core metrics API is now built on
>> RxJava, function params and return types should probably be
>> rx.Observable. Some of the work described below may already be covered
>> by the work Jay did for HWKMETRICS-144 which involved adding
>> min/max/avg functions. To be honest, I think functions like
>> min/max/avg are poor candidates for some of the changes being
>> discussed because they are so simple. Here is our avg function,
>>
>> Func1<Observable<DataPoint<Double>>, Observable<Double>> Average =
>> data ->
>> MathObservable.averageDouble(data.map(DataPoint::getValue));
>>
>> For other, more involved functions, I think we should look first at
>> the core operators in Rx.Observable and then maybe consider custom
>> operators[1].
>>
>> [1]
>> https://github.com/ReactiveX/RxJava/wiki/Implementing-Your-Own-Operators
>>
>>> On Jul 21, 2015, at 5:43 AM, Thomas Segismont <tsegismo at redhat.com
>>> <mailto:tsegismo at redhat.com>> wrote:
>>>
>>> Hi,
>>>
>>> I have looked at Aakarsh's repo:
>>> https://github.com/Akki5/hawkular_plugin/
>>>
>>> It's a good start with an interface describing a doubles to double
>>> function, a classloader for implementation loading and a set of initial
>>> implementations.
>>>
>>> In order to integrate this work into Metrics, I think we should follow
>>> the following steps:
>>>
>>> =====
>>> #1 Change the contract
>>>
>>> Doubles to double works great for avg/min/max/... functions on gauge
>>> metrics. But we need to consider other metric types.
>>>
>>> Also, the interface should not only accept data point values, but whole
>>> data points. Because some functions need the timestamp to compute the
>>> result. % of up availability is a good example.
>>>
>>> And functions may return different types: Double, Long, AvailabilityType.
>>>
>>> #2 Update configuration options to let the user set a plugins directory
>>>
>>> Metrics doc needs will have to be updated.
>>>
>>> #3 Create a function repository for each metric type
>>>
>>> We can build on JDK's service loader + Aakarsh's classloader
>>> implementation.
>>>
>>> #4 Add builtin aggregate functions
>>>
>>> Extract existing Metrics code (min, max, avg, % of up avail, downtime
>>> duration) into builtin functions.
>>>
>>> #5 Document the process of implementing a pluggable function
>>>
>>> We need to think about function naming as well. Should we use a prefix
>>> to identify a builtin function?
>>> =====
>>>
>>> I will start another thread to discuss REST and Core API data query
>>> changes.
>>>
>>> Thoughts?
>>>
>>> Thanks,
>>> Thomas
>>> _______________________________________________
>>> hawkular-dev mailing list
>>> hawkular-dev at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/hawkular-dev
>>
>>
>>
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>
>
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